Soldering iron



F. L- DARLING SOLDERING IRON July 5, 1949.

m P w m F m m ATTORNEY.

Patented July 5, 1949 UNITED STATES PATENT OFFICE SOLDERING IRON" FrankL. Darling, Hollywood, Calif., .assignor a A. P. Drayto'n, LosAngeles;:alif.

Application February 28, 1946, SerialNo. 650,812

3 Claims.

1 My invention relates to soldering irons of the electrically heatedtype. its objects:

L 'io provide an iron of relatively light weight.

2. To provide an iron in which the expansion of the heated part servesas a thermostat to con trol a circuit breaker.

. To provide an iron in which the temperature may be set by the user andautomatically controlled for any heat from zero to 560 degrees.

. To provide for the operation of the circuit breaker to open thecircuit by a pull action, thereby avoiding stacking the connection andcausing inaccurate operation.

. To provide an iron with a thermostatic control such that the circuitwill be opened at the proper time even though the contact points shouldStick.

6. To provide an iron with a new kindof tip that can easily and cheaplybe replaced when nec essary.

7. To provide means to reduce to a minimum heat conduction from the ironproper to the handle.

Other objects will in part be obvious and in part will be pointed outhereinafter.

To the attainment of the aforesaidobjects and ends the invention-furtherresides in those novel details of construction, combination andarrangement of parts, all of which will be first described in detailhereinafter and will then be specifically pointed out in the appendedclaims, reference being had to the accompanying drawing, in which:

Fig. 1 is a plan view of an iron according to my invention.

Fig. 2 is a part central horizontal section and part plan view of thesame with the cover part of the handle omitted.

Fig. 3 is a central vertical longitudinal section of the handle and theparts contained therein.

Fig. 4 is an inverted plan View of the circuit breakerplate and theparts carried by it.

Fig. 5 is a face view of the handle-coupling member looking from left toright in Fig. 3;

Fig. 6 is a section on the line 6-6 of Fig. 2 looking in the directionof the arrow, the insulation spacers and connecting screws beingomitted.

Fig. '7 is a detail section, on the line l-l of Fig. 6, of theiron-coupling plate.

Fig. 8 is a detail view hereinafter specifically referred to.

In the drawing, in which like numerals of reference indicate like partsin all figures, l represents the part of the instrument to which theheat is applied (commonly referred to as the "iron). In

The invention has for- 2, my instrument the part I is made of a suitablealuminum alloy. It iscylindrical in form and has a-fiange 2 and apyramidal tip 4 connected with theflange partby a neck 3. The pyramidaltip 4 is covered by a stamped metal (copper) sheath 5 whichis r'emovablyheld tightly in place by crimping over portions ofits inner edge as at5*. At its innerend-the iron I is threaded into the-threaded hole 1 of acoupling plate or ring ii. l7he iron I isbored as at l to receive theanchor for-the pull wire-29,.later again referred to.

ihe plate t has screw holes 3 for connecting screws to join-platento theintermediate ring i l, insulators l2 being interposed through whichinsulators the connecting screws are passed. The plate 6 also has airholes}.

A heating: coil I0 is placedon the member l between the-fiange 2and-theiron-coupling member 8; andametal shield IT is placed overthesame, as shown in Figs. 1 and 2.

The handle-unit is best shown in'Figs. 2 and 3 by reference-to whichitw-ill be seen that H3 is the handle of suitable: material that is apoor conductorof heat- Thehandle is 'hollow and is cut apart as at2Eltoprovide a removable cover 22 which is heldin-place by screws-23,the longer one of which passes through a hole in the insulation baseplate 25 and threads into a fixed part of the handle while the shorterscrew is threadedinto-a saddle 21. The outer end of the handle isbored-and bushed as at 24 to pass in thepower'wires 56 and 57. Thehandle it is mounted on the mounting bushing l5 and held thereon by ascrew l9.- Themounting bushing I5 is integrally formed withahandle-coupling flange it which isconnectedto-ringl l by screws 16which pass through holes 8 in fiange I4" and insulation l3,-andare-screwed'irito'ringv H at-places stagger-ed with'res-pectto thescrews and screw holes :ofplate 6.

Flange idalso-has-yent-holes: W. The handle hasrecessed portions l8 inwhich' the circuit breaker base plate flr rests-and is held in place bythe cover 22.

Mounted on the base plate 25 is an L-shaped lever 35 whose longer legcarries a contact point 31, and whose shorter leg is pivoted at 38. Apin 38, carried by the longer leg, projects through a slot 39 in thebase plate 25 and is engaged by a return spring Mi. The spring ill isanchored at 52 and passes over a fixed pin ll on the plate 23 so thatthe spring All constantly urges the lever 35 toward its circuit-closingposition. Also mounted on the plate 25 is a lever iii that is pivoted atone end, as at 44, and carries a contact point iii to cooperate withcontact point 31, the extreme or free end of the lever being held incontact with a temperature regulating cam 52 by means of a spring 48which is anchored at '59, passes over a fixed pin 49 and engages a pin49 on the lever 43. The pin 46 passes through a slot ill.

The cam 52 is carried by an adjusting bolt or screw 9i that passesthrough and is soldered to a washer M. The bolt also passes through ahole in plate 25 and the cam 52 is held to the bolt by a nut 53. Thewasher 54 has a mark and the handle has H and L marks to indicate highand low temperature adjustments.

The wire 29 is attached in any suitable way (as by welding) to the screw32 and to the anchor 39. The anchor 30 is held in place by the key pin31 in the neck 3. The screw 32 is ad justably threaded into a slide 21which works in a groove or recess 26 in plate 25 and has a pin 29 toengage the shorter arm of the lever 35. A nut 93 holds screw 32 inplace. When the tool is cold, pin 28 is free of lever 35 but when thetool heats up, expansion of the member I exerts a pull on wire 29,causing pin 28 to contact lever 95 and. when the right temperature isreached moves lever 35 to break the circuit. The temperature at whichthe circuit is broken depends on the position to which cam 52 is set.The tool is set for its maximum heat when lever 43 is engaged by the lowside of the cam, and by turning the cam settings for any desired degreeof heat less than maximum can be had and controlled at that setting. Asshown, the tool is set for maximum heat.

One power wire 58 runs direct to coil 19, an other 57 runs to pin 46,while a third wire 55 connects coil it with pin 38. A piece of sheetinsulation 34- prevents possible short circuits to bushing I5.

The tool which I have constructed accordin to this disclosure can be setto operate from a maximum of 500 watts down to 50 watts. As will beseen, the control is very positive as it is operated by the expansion ofthe part i actin on the circuit breaker with a pull through wire 29sufficient to break apart the points, even though they should stick moreor less. Of course, as will be obvious to anyone skilled in the art, thewire 29 should have a lesser co-efiicient of expansion than the materialof part I or it must be kept cooler than part I or both. The coupling 9,12, II, I3, [4 not only lessens heat conduction between the handleportion and the heating portion of the tool but serves to ventilatesomewhat the space containing the wire 29 thereby cooling it below thetemperature of part I.

The new style copper tip is an important improvement. These tips can bestamped from onesixteenth inch copper at low cost and sold to the usersof the tools as replacement points. This does away with the usualpractice of screwing copper tips into the heating elements; as thesepoints oxidize rapidly, it is frequently impossible to screw the tipsout without ruining the irons for replacement. My tip 5 can be easilypried off with an ordinary screw driver and a new one can be installedinstantly.

By the new construction of my tool I have reduced the weight of a 500watt iron to less than one-half of that of one of the best irons now onthe market.

From the foregoing description, taken in connection with the accompanyindrawing, it is thought that the construction, operation, and advantagesof the invention will be clear to those skilled in the art.

What I claim is:

1. In an electrically heated soldering iron, two units one of which is achambered heating unit and the other of which is a handle and aheatcontrolling unit; a heat-insulating and chamber ventilating couplingjoining said units together; and means anchored to the heating unit andlying in the chambers of said units and mechanically connected to theheat-controlling unit operable by the expansion and contraction oi theheating unit for effecting operation of the heat-controllinginstrumentalities of the heatcontrolling unit.

2. In an electrically heated soldering iron, heating unit and a handle,said units having connecting chambers; a ventilated coupling be tweensaid units and effecting communication between said chambers and. theatmosphere; a circuit make and break device mounted in said handle; anda pull connection between said device and the heating unit operable bythe expan-- sion and contraction of the heating unit in use, said pullconnection lying within said chambers.

3. In an electrically heated soldering iron, expansible and contractableelement to be heated which has a bore and a tip; an electric heatingcoil on said element; a handle having a chamher; a ventilated insulatedcoupling between said element and said handle and communicating withsaid bore and said chamber and the atmosphere; a circuit opening andclosing device mounted in said handle and including a shiftableoperating element; a wire anchored at one of its ends in said bore andconnected at its other end to said shiftable operating element; and anelec tric circuit including said heating coil and said circuit openingand closing device.

FRANK L. DARLING.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number

